Process of preparing



(No Model.) v

R. R. WAITZ.

PROCESS 0E PREPARING REFRAGIORY ORES FOR AMALGAMATION. No. 247,972.Patented ct. 4,1881.

X4320 Til/6,00.

. [PROM/r6 nJma/cz. U r I- UNITED STATES.

PATENT OFFICE. 1

ROBERT R. WAITZ, OF ROSITA, COLORADO.

PROCESS OF PREPARING REFRACTORY ORES FOR AMALGAMATION.

SPECIFICATION forming part of Letters Patent No. 247,972, dated October4, 1881. Application filed September 9, 1881. (No model.)

declare the following to be a full, clear, and

.' exact description of theinvention,such as will enable others skilledin the art to which it appertains to make and use the same, referencebeing bad to the accompanying drawing, and to letters or figures ofreference marked thereon, which form a part ofthis specification.

The object of my invention is to furnish a process for treatingrefractory anriferous and argentiferous ores, by means of which the basemetals contained in said ores are thoroughly and quickly converted intoinsoluble oxides, and all volatile matters decomposed and expelled fromthe furnace. I attain the results stated by heating the pulverized orein a scientific manner in a furnaee or chamber from which atmosphericair is excluded, as will hereinafter he more fully set forth, and thenindicated in the claim.

In carrying out my process I pnlveri'ze or comminute the ore containingthe precious metals, and add thereto, before or after its introductioninto a furnace or heating-chamber, any well-known oxygenated agent or.substance-such as dioxide of manganese, chlorate of potassium, orferric oxide. These substances may be used singly, or two of the same orall three may be combined. The proportions in which they are useddepends altogether upon circumstances or the character of the ores,because the latter frequently contain the aforesaid substances. It is anessential requisite that no sulphates shall be presentin the ore whenthe same is undergoing the process of amalgamation, and for this reasonI also add to the ore, before or after its introduction into thefurnace,an agent or substance which will serve to decompose the sulphatesformedparticularly sulphate of copper. In certain instances thecarbonic-acid gas evolved by the combustion of fuel in the fire-chamberof the furnace will serve to accomplish the result stated. When. copperpyrites are being treated I preferably add thereto a sufficient quantityof the well-known reagent-carbonate of ammonium-for decomposiu gsulphates. In this instance the latter are converted into volatilesulphate of ammonia, which passes 01f.

It has already been stated that the invention consists chiefly in ascientific manner of heating the ores, and I will now proceed to fullydescribe the same, reference being bad to the accompanying drawing,which illus- 6o trates a furnace preferably employed for carrying out myprocess.

The pulverized ore is fed into a closed flue or chamber, andis conductedor passed through the same in the form of a thin stratum or 6 body,whichis in constant motion from the inlet to the outlet openings. In theform of furnace illustrated in the drawing the ore moves by its owngravity through aninclined flue or chamber, and is discharged upon ahori- 7o zontal hearth or sole located in juxtaposition to the grate orfire chamber. It will be manifest, however, that the ore can be moved bymechanical means through a horizontal flue or chamber. The flames andheated gases issuing 7 5 from the fire or grate chamber pass through theflue or ore-treating chamber and obviously cause an excess of oxygento'evolve from the oxygenated substances contained in the ore. The thinstratum or body of ore will enable this result to take place in anexpeditious and perfect manner, because the sheet of flame is broughtinto intimate contact with the ore.

It is necessary to the proper heating orroasting of ores that the samebe heated gradually, 8 5 so as to obviate the fusion of sulphides at theoutset and prevent the formation of a matte troublesome to roast. In myprocess the ac- 1 tion of the heat is, as just stated, because the oreis constantly moving from the feed-hopper o farthest from thefire-chamber to the disch argepassage in proximity to the latter.

The liberation of oxygenby heat in the manner above indicated will notonly serve to effeet the perfect oxidation of the base metals 5 without.the aid of an air-blast or current of atmospheric air, but will alsotend to supply the necessary amount of oxygen to the firechamber forsupporting the combustion of fuel therein. 10:)

It will be obvious that the descending or moving body of ore will effecta back action of the oxygen existing near the fire-chamber, and forcethe same into the latter; hence it is possible to support combustionwith closed furnace-doors, there being no admission whatever ofatmospheric air.

h'ly process is specially designed for treating refractory ores ofprecious metals, because I am able to perform the heating operation witha small consumption of fuel and in a comparatively brief period oftimeone to two hours. The roasted ore passing from the furnace containsthe precious metals in a pure metallic state, and as all base metalshave been converted into insoluble oxides and the sulphates decomposed,the process of amalgamation with mercury can be performed in a thoroughand expeditious manner.

I am aware that it is not new to add oxygenated substances to ores whileundergoing the roasting operation in a furnace having means foradmitting atmospheric air, and devoid of devices for propelling the ore.It has also been proposed to roast ores, mixed with oxidizing agents, ina retort or closed cylinder revolvingjn afirechamber, and having asteam-jet pipe leading into said retort.

I am also aware that ore has has been passed through a flue orroasting-chamber in the form of a thin stream or stratum movingconstantly from inlet to outlet, and subjected to the oxidizing actionof a current of atmospheric air and heated gases.

I disclaim the various steps of ny process separately considered, andconfine myself to the combination ofsteps herein set forth, whichpromise a success much surer and a roasting far better and expeditiousthan by any other process heretofore proposed.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent,is

The process of desulphurizing and oxidizing refractory auriferousandargentiferous ores, consisting in subjecting a thin body or stratum ofore, moving constantly through a closed chamber from which air isexcluded, to the direct contact of a caloric current or sheet of flame,and of oxygen, evolved by the decomposition of oxygenated agentscontained in the ore, through the medium of heat, the oxygen soobtained, in addition to its oxidizing action, serving to supportcombustion in the ore-chamber, and in a firechamber communicatingdirectly with the latter, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

